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| author | Richard Henderson <richard.henderson@linaro.org> | 2021-11-15 14:08:52 +0100 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2021-12-19 20:47:33 -0800 |
| commit | a3310c0397e21df8f47cde3e55736104b9584d2d (patch) | |
| tree | 2e550417028aea39886ba22f4b60fb9c88404630 /linux-user/host/ppc64 | |
| parent | b9d2af3c62c22870c02410d5c9c6d097ee0ddf3f (diff) | |
| download | qemu-a3310c0397e21df8f47cde3e55736104b9584d2d.zip qemu-a3310c0397e21df8f47cde3e55736104b9584d2d.tar.gz qemu-a3310c0397e21df8f47cde3e55736104b9584d2d.tar.bz2 | |
linux-user: Move syscall error detection into safe_syscall_base
The current api from safe_syscall_base() is to return -errno, which is
the interface provided by *some* linux kernel abis. The wrapper macro,
safe_syscall(), detects error, stores into errno, and returns -1, to
match the api of the system syscall().
For those kernel abis that do not return -errno natively, this leads
to double syscall error detection. E.g. Linux ppc64, which sets the
SO flag for error.
Simplify the usage from C by moving the error detection into assembly,
and usage from assembly by providing a C helper with which to set errno.
Reviewed-by: Warner Losh <imp@bsdimp.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'linux-user/host/ppc64')
| -rw-r--r-- | linux-user/host/ppc64/safe-syscall.inc.S | 24 |
1 files changed, 11 insertions, 13 deletions
diff --git a/linux-user/host/ppc64/safe-syscall.inc.S b/linux-user/host/ppc64/safe-syscall.inc.S index 4b57440..3a640cf 100644 --- a/linux-user/host/ppc64/safe-syscall.inc.S +++ b/linux-user/host/ppc64/safe-syscall.inc.S @@ -22,9 +22,6 @@ * first argument an 'int *' to the signal_pending flag, the * second one the system call number (as a 'long'), and all further * arguments being syscall arguments (also 'long'). - * We return a long which is the syscall's return value, which - * may be negative-errno on failure. Conversion to the - * -1-and-errno-set convention is done by the calling wrapper. */ #if _CALL_ELF == 2 safe_syscall_base: @@ -39,7 +36,7 @@ safe_syscall_base: .L.safe_syscall_base: .cfi_startproc #endif - /* We enter with r3 == *signal_pending + /* We enter with r3 == &signal_pending * r4 == syscall number * r5 ... r10 == syscall arguments * and return the result in r3 @@ -71,21 +68,22 @@ safe_syscall_start: /* if signal_pending is non-zero, don't do the call */ lwz 12, 0(14) cmpwi 0, 12, 0 - bne- 0f + bne- 2f sc safe_syscall_end: /* code path when we did execute the syscall */ - ld 14, 16(1) /* restore r14 to its original value */ - bnslr+ - - /* syscall failed; return negative errno */ - neg 3, 3 + ld 14, 16(1) /* restore r14 */ + bso- 1f blr /* code path when we didn't execute the syscall */ -0: addi 3, 0, -TARGET_ERESTARTSYS - ld 14, 16(1) /* restore r14 to its original value */ - blr +2: ld 14, 16(1) /* restore r14 */ + addi 3, 0, TARGET_ERESTARTSYS + + /* code path setting errno */ +1: b safe_syscall_set_errno_tail + nop /* per abi, for the linker to modify */ + .cfi_endproc #if _CALL_ELF == 2 |